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Sharma S, Satheesan A, Majumdar A, Mukherjee S, Basu A. PARP-16 regulates the PERK and IRE-1α Mediated Unfolded Protein Response in Japanese Encephalitis Virus-Infected Neural Stem/Progenitor Cells. Mol Neurobiol 2025; 62:8084-8096. [PMID: 39979689 DOI: 10.1007/s12035-025-04748-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 02/06/2025] [Indexed: 02/22/2025]
Abstract
The viral infection and subsequent accumulation of viral proteins in the infected cells leads to endoplasmic reticulum (ER) stress. Japanese encephalitis virus (JEV) infection in the Central Nervous System (CNS) has been shown to induce unfolded protein response (UPR). The ER stress is resolved by the UPR which comprises certain signals that are transduced from the ER either to both the cytoplasm or nucleus, resulting in the adaptation for survival or may even lead to apoptosis. Here, we demonstrate that Poly ADP-ribose polymerase-16 (PARP-16) expression is regulating the ER stress response following JEV infection of Neural Stem/Progenitor cells (NSPCs) in the BALB/c mouse model. Activation of the key sensors of UPR, namely, protein kinase R (PKR)-like ER kinase (PERK) and Inositol-requiring enzyme-1α (IRE-1α) by PARP-16 upon JEV infection, led to the activation of their downstream signalling cascade. The siRNA-mediated in vitro downregulation of PARP-16 in NSPCs alleviated the overall UPR, as the abundance of UPR markers and their downstream modulators of signalling cascade was found to be downregulated. These results highlight an important role of PARP-16 during JEV infection of NSPCs.
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Affiliation(s)
- Shivangi Sharma
- National Brain Research Centre, Manesar, Haryana, 122052, India
- Department of Physiology and Pathophysiology, Spinal Cord Research Centre, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, R3E0J9, Canada
| | | | - Atreye Majumdar
- National Brain Research Centre, Manesar, Haryana, 122052, India
| | - Sriparna Mukherjee
- National Brain Research Centre, Manesar, Haryana, 122052, India
- Department of Pharmacology and Physiology, Pavilion Roger-Gaudry, Universite de Montréal, Montréal, Québec, Canada
| | - Anirban Basu
- National Brain Research Centre, Manesar, Haryana, 122052, India.
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2
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Zavarzadeh PG, Panchal K, Bishop D, Gilbert E, Trivedi M, Kee T, Ranganathan S, Arunagiri A. Exploring proinsulin proteostasis: insights into beta cell health and diabetes. Front Mol Biosci 2025; 12:1554717. [PMID: 40109403 PMCID: PMC11919908 DOI: 10.3389/fmolb.2025.1554717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2025] [Accepted: 02/13/2025] [Indexed: 03/22/2025] Open
Abstract
Proinsulin misfolding is central to diabetes. This review examines the cellular mechanisms regulating proinsulin proteostasis in pancreatic β-cells, encompassing genetic factors such as insulin gene mutations, and exploring the roles of endoplasmic reticulum (ER) stress and the unfolded protein response (UPR), ER redox balance, mitochondrial function, and the influence of extrinsic factors. Mutations in the INS gene, particularly those affecting cysteine residues, impair folding and disulfide bond formation, often exhibiting dominant-negative effects on the wild-type proinsulin. The importance of ER quality control mechanisms, including chaperones and oxidoreductases, in facilitating proper folding and degradation of misfolded proinsulin is emphasized. Disruptions in these systems, due to genetic mutations, ER stress, or impaired ER-to-Golgi trafficking, lead to proinsulin accumulation and β-cell dysfunction. The unfolded protein response (UPR), especially the PERK and IRE1α-XBP1 pathways, emerges as a central regulator of protein synthesis and ER stress management. The review also discusses the role of mitochondrial health, ER redox state, and extrinsic factors such as diet and medications in influencing proinsulin proteostasis. Finally, the structural insights from NMR and molecular dynamics simulations are discussedhighlighting the dynamics of misfolding and underscoring the importance of disulfide bonds. These mechanistic insights suggest innovative strategies targeting thiol/disulfide redox systems in cells to mitigate protein misfolding diseases including diabetes.
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Affiliation(s)
| | - Kathigna Panchal
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN, United States
| | - Dylan Bishop
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN, United States
| | - Elizabeth Gilbert
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN, United States
| | - Mahi Trivedi
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN, United States
| | - Tovaria Kee
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN, United States
| | | | - Anoop Arunagiri
- Department of Biological Sciences, East Tennessee State University, Johnson City, TN, United States
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3
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Jo A, Jung M, Mun JY, Kim YJ, Yoo JY. Membrane-tethered SCOTIN condensates elicit an endoplasmic reticulum stress response by sequestering luminal BiP. Cell Rep 2025; 44:115297. [PMID: 39946235 DOI: 10.1016/j.celrep.2025.115297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2024] [Revised: 01/10/2025] [Accepted: 01/21/2025] [Indexed: 02/28/2025] Open
Abstract
The endoplasmic reticulum (ER) stress response controls the balance between cellular survival and death. Here, we implicate SCOTIN, an interferon-inducible ER protein, in activating the ER stress response and modulating cell fate through its proline-rich domain (PRD)-mediated cytosolic condensation. SCOTIN overexpression leads to the formation of condensates enveloping multiple layers of the ER, accompanied by morphological signs of organelle stress. Luminal BiP chaperone proteins are sequestered within these SCOTIN condensates, which elicit ER stress responses. The colocalization of luminal BiP with SCOTIN is strictly contingent upon the PRD-mediated condensation of SCOTIN in the cytosolic compartment, closely associated with the ER membrane. The cysteine-rich domain (CRD) of SCOTIN, along with the condensation-prone PRD domain, is required for ER stress induction. We propose that membrane-associated condensation transduces signals across the ER membrane, leading to the induction of BiP assembly and the ER stress response.
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Affiliation(s)
- Areum Jo
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Minkyo Jung
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu 41062, Republic of Korea
| | - Ji Young Mun
- Neural Circuit Research Group, Korea Brain Research Institute, Daegu 41062, Republic of Korea
| | - Young Jin Kim
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Joo-Yeon Yoo
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, Republic of Korea.
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4
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Liu G, Wu J, Wang Y, Xu Y, Xu C, Fang G, Li X, Chen J. The Differential Expressions and Associations of Intracellular and Extracellular GRP78/Bip with Disease Activity and Progression in Rheumatoid Arthritis. Bioengineering (Basel) 2025; 12:58. [PMID: 39851332 PMCID: PMC11761566 DOI: 10.3390/bioengineering12010058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2024] [Revised: 12/31/2024] [Accepted: 01/09/2025] [Indexed: 01/26/2025] Open
Abstract
GRP78/BiP, a stress-induced protein and autoantigen in rheumatoid arthritis (RA), exhibits different expressions in various biological fluids and tissues, including blood, synovial fluid (SF), and synovium, all of which are pertinent to the disease activity and progression of RA; however, there is a scarcity of data linking both intracellular and extracellular GRP78/Bip to disease activity and progression of RA. This study was undertaken to investigate the differential expression of GRP78/Bip in blood, SF, and synovium, and to determine their association with disease activity and progression of RA. Patients with RA, osteoarthritis (OA), and traumatic meniscal injury (TMI) without radiographic OA were consecutively recruited for the study. Among patients with RA, six different subgroups were established based on their disease activity and progression. Disease activity was measured using the DAS28 (Disease activity scores in 28 joints) criterion, while disease progression was evaluated using the Steinbrocker classification grade. The levels of GRP78/Bip, TNF-α, and IL-10 were significantly elevated in the serum, SF, and synovium of patients with RA when compared to both the control (CON, TMI Patients) and the inflammation control (iCON, OA Patients) groups (p < 0.05). In terms of disease activity status, as opposed to remission status in RA, the levels of GRP78/Bip, TNF-α, and IL-10 were all elevated in serum and synovium (p < 0.05). However, GRP78/Bip and IL-10 levels were found to be reduced in SF, while TNF-α levels remained elevated. With respect to disease progression in RA, GRP78/Bip levels exhibited a positive correlation with both the stage of RA and the levels of TNF-α and IL-10 in serum and synovium. Nonetheless, a negative correlation was observed between GRP78/Bip levels and the stage of RA in SF, while positive correlations with the levels of TNF-α and IL-10 persisted. The differential expression of GRP78/Bip in blood, SF, and synovium indicated that the potential role and function of GRP78/Bip might vary depending on its specific location within these biological fluids and tissues. The presence of intracellular and extracellular GRP78/Bip was associated with disease activity and progression of RA, suggesting the involvement of GRP78/Bip in the pathogenesis and development of this debilitating autoimmune disorder, as well as its potential as a biomarker for monitoring disease activity and progression of RA.
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Affiliation(s)
- Guoyin Liu
- Department of Orthopedics, The Affiliated Jinling Hospital of Nanjing Medical University, Nanjing 211166, China; (G.L.); (Y.X.)
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Jianping Wu
- Department of Obstetrics, The Affiliated Jinling Hospital of Nanjing Medical University, Nanjing 211166, China;
| | - Yongqiang Wang
- Department of Rehabilitation, The Affiliated Jinling Hospital of Nanjing Medical University, Nanjing 211166, China;
| | - Yuansheng Xu
- Department of Orthopedics, The Affiliated Jinling Hospital of Nanjing Medical University, Nanjing 211166, China; (G.L.); (Y.X.)
| | - Chun Xu
- Department of Pathology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210008, China;
| | - Guilin Fang
- Department of Rheumatology, The Affiliated Jinling Hospital of Nanjing Medical University, Nanjing 211166, China;
| | - Xin Li
- Department of Orthopedics, Central Military Commission Joint Logistics Support Force 904th Hospital, Wuxi 214044, China
| | - Jianmin Chen
- Department of Orthopedics, The Affiliated Jinling Hospital of Nanjing Medical University, Nanjing 211166, China; (G.L.); (Y.X.)
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Dawes S, Hurst N, Grey G, Wieteska L, Wright NV, Manfield IW, Hussain MH, Kalverda AP, Lewandowski JR, Chen B, Zhuravleva A. Chaperone BiP controls ER stress sensor Ire1 through interactions with its oligomers. Life Sci Alliance 2024; 7:e202402702. [PMID: 39103227 PMCID: PMC11300964 DOI: 10.26508/lsa.202402702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 07/24/2024] [Accepted: 07/24/2024] [Indexed: 08/07/2024] Open
Abstract
The complex multistep activation cascade of Ire1 involves changes in the Ire1 conformation and oligomeric state. Ire1 activation enhances ER folding capacity, in part by overexpressing the ER Hsp70 molecular chaperone BiP; in turn, BiP provides tight negative control of Ire1 activation. This study demonstrates that BiP regulates Ire1 activation through a direct interaction with Ire1 oligomers. Particularly, we demonstrated that the binding of Ire1 luminal domain (LD) to unfolded protein substrates not only trigger conformational changes in Ire1-LD that favour the formation of Ire1-LD oligomers but also exposes BiP binding motifs, enabling the molecular chaperone BiP to directly bind to Ire1-LD in an ATP-dependent manner. These transient interactions between BiP and two short motifs in the disordered region of Ire1-LD are reminiscent of interactions between clathrin and another Hsp70, cytoplasmic Hsc70. BiP binding to substrate-bound Ire1-LD oligomers enables unfolded protein substrates and BiP to synergistically and dynamically control Ire1-LD oligomerisation, helping to return Ire1 to its deactivated state when an ER stress response is no longer required.
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Affiliation(s)
- Sam Dawes
- School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
- Chemistry Department, University of Sheffield, Sheffield, UK
| | - Nicholas Hurst
- School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Gabriel Grey
- School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Lukasz Wieteska
- School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Nathan V Wright
- School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Iain W Manfield
- School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Mohammed H Hussain
- School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Arnout P Kalverda
- School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | | | - Beining Chen
- Chemistry Department, University of Sheffield, Sheffield, UK
| | - Anastasia Zhuravleva
- School of Molecular and Cellular Biology, Faculty of Biological Sciences & Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
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Kettel P, Karagöz GE. Endoplasmic reticulum: Monitoring and maintaining protein and membrane homeostasis in the endoplasmic reticulum by the unfolded protein response. Int J Biochem Cell Biol 2024; 172:106598. [PMID: 38768891 DOI: 10.1016/j.biocel.2024.106598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 05/01/2024] [Accepted: 05/14/2024] [Indexed: 05/22/2024]
Abstract
The endoplasmic reticulum (ER) regulates essential cellular processes, including protein folding, lipid synthesis, and calcium homeostasis. The ER homeostasis is maintained by a conserved set of signaling cascades called the Unfolded Protein Response (UPR). How the UPR senses perturbations in ER homeostasis has been the subject of active research for decades. In metazoans, the UPR consists of three ER-membrane embedded sensors: IRE1, PERK and ATF6. These sensors detect the accumulation of misfolded proteins in the ER lumen and adjust protein folding capacity according to cellular needs. Early work revealed that the ER-resident chaperone BiP binds to all three UPR sensors in higher eukaryotes and BiP binding was suggested to regulate their activity. More recent data have shown that in higher eukaryotes the interaction of the UPR sensors with a complex network of chaperones and misfolded proteins modulates their activation and deactivation dynamics. Furthermore, emerging evidence suggests that the UPR monitors ER membrane integrity beyond protein folding defects. However, the mechanistic and structural basis of UPR activation by proteotoxic and lipid bilayer stress in higher eukaryotes remains only partially understood. Here, we review the current understanding of novel protein interaction networks and the contribution of the lipid membrane environment to UPR activation.
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Affiliation(s)
- Paulina Kettel
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria; Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - G Elif Karagöz
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria; Medical University of Vienna, Vienna, Austria.
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7
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Casas-Martinez JC, Samali A, McDonagh B. Redox regulation of UPR signalling and mitochondrial ER contact sites. Cell Mol Life Sci 2024; 81:250. [PMID: 38847861 PMCID: PMC11335286 DOI: 10.1007/s00018-024-05286-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/11/2024] [Accepted: 05/18/2024] [Indexed: 06/13/2024]
Abstract
Mitochondria and the endoplasmic reticulum (ER) have a synergistic relationship and are key regulatory hubs in maintaining cell homeostasis. Communication between these organelles is mediated by mitochondria ER contact sites (MERCS), allowing the exchange of material and information, modulating calcium homeostasis, redox signalling, lipid transfer and the regulation of mitochondrial dynamics. MERCS are dynamic structures that allow cells to respond to changes in the intracellular environment under normal homeostatic conditions, while their assembly/disassembly are affected by pathophysiological conditions such as ageing and disease. Disruption of protein folding in the ER lumen can activate the Unfolded Protein Response (UPR), promoting the remodelling of ER membranes and MERCS formation. The UPR stress receptor kinases PERK and IRE1, are located at or close to MERCS. UPR signalling can be adaptive or maladaptive, depending on whether the disruption in protein folding or ER stress is transient or sustained. Adaptive UPR signalling via MERCS can increase mitochondrial calcium import, metabolism and dynamics, while maladaptive UPR signalling can result in excessive calcium import and activation of apoptotic pathways. Targeting UPR signalling and the assembly of MERCS is an attractive therapeutic approach for a range of age-related conditions such as neurodegeneration and sarcopenia. This review highlights the emerging evidence related to the role of redox mediated UPR activation in orchestrating inter-organelle communication between the ER and mitochondria, and ultimately the determination of cell function and fate.
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Affiliation(s)
- Jose C Casas-Martinez
- Discipline of Physiology, School of Medicine, University of Galway, Galway, Ireland
- Apoptosis Research Centre, University of Galway, Galway, Ireland
| | - Afshin Samali
- Apoptosis Research Centre, University of Galway, Galway, Ireland
- School of Biological and Chemical Sciences, University of Galway, Galway, Ireland
| | - Brian McDonagh
- Discipline of Physiology, School of Medicine, University of Galway, Galway, Ireland.
- Apoptosis Research Centre, University of Galway, Galway, Ireland.
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Carrillo R, Iwai K, Albertson A, Dang G, Christopher DA. Protein disulfide isomerase-9 interacts with the lumenal region of the transmembrane endoplasmic reticulum stress sensor kinase, IRE1, to modulate the unfolded protein response in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2024; 15:1389658. [PMID: 38817940 PMCID: PMC11137178 DOI: 10.3389/fpls.2024.1389658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 04/19/2024] [Indexed: 06/01/2024]
Abstract
Environmental stressors disrupt secretory protein folding and proteostasis in the endoplasmic reticulum (ER), leading to ER stress. The unfolded protein response (UPR) senses ER stress and restores proteostasis by increasing the expression of ER-resident protein folding chaperones, such as protein disulfide isomerases (PDIs). In plants, the transmembrane ER stress sensor kinase, IRE1, activates the UPR by unconventionally splicing the mRNA encoding the bZIP60 transcription factor, triggering UPR gene transcription. The induced PDIs catalyze disulfide-based polypeptide folding to restore the folding capacity in the ER; however, the substrates with which PDIs interact are largely unknown. Here, we demonstrate that the Arabidopsis PDI-M subfamily member, PDI9, modulates the UPR through interaction with IRE1. This PDI9-IRE1 interaction was largely dependent on Cys63 in the first dithiol redox active domain of PDI9, and Cys233 and Cys107 in the ER lumenal domain of IRE1A and IRE1B, respectively. In vitro and in vivo, PDI9 coimmunoprecipitated with IRE1A and IRE1B. Moreover, the PDI9:RFP and Green Fluorescence Protein (GFP):IRE1 fusions exhibited strong interactions as measured by fluorescence lifetime imaging microscopy-fluorescence resonance energy transfer (FLIM-FRET) when coexpressed in mesophyll protoplasts. The UPR-responsive PDI9 promoter:mCherry reporter and the UPR-dependent splicing of the bZIP60 intron from the mRNA of the 35S::bZIP60-intron:GFP reporter were both significantly induced in the pdi9 mutants, indicating a derepression and hyperactivation of UPR. The inductions of both reporters were substantially attenuated in the ire1a-ire1b mutant. We propose a model in which PDI9 modulates the UPR through two competing activities: secretory protein folding and via interaction with IRE1 to maintain proteostasis in plants.
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Affiliation(s)
| | | | | | | | - David A. Christopher
- Department of Molecular Biosciences and Bioengineering, University of Hawaii, Honolulu, HI, United States
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9
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Xu J, Sabatino B, Yan J, Ermakova G, Doering KRS, Taubert S. The unfolded protein response of the endoplasmic reticulum protects Caenorhabditis elegans against DNA damage caused by stalled replication forks. G3 (BETHESDA, MD.) 2024; 14:jkae017. [PMID: 38267027 PMCID: PMC10989892 DOI: 10.1093/g3journal/jkae017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 12/21/2023] [Accepted: 01/14/2024] [Indexed: 01/26/2024]
Abstract
All animals must maintain genome and proteome integrity, especially when experiencing endogenous or exogenous stress. To cope, organisms have evolved sophisticated and conserved response systems: unfolded protein responses (UPRs) ensure proteostasis, while DNA damage responses (DDRs) maintain genome integrity. Emerging evidence suggests that UPRs and DDRs crosstalk, but this remains poorly understood. Here, we demonstrate that depletion of the DNA primases pri-1 or pri-2, which synthesize RNA primers at replication forks and whose inactivation causes DNA damage, activates the UPR of the endoplasmic reticulum (UPR-ER) in Caenorhabditis elegans, with especially strong activation in the germline. We observed activation of both the inositol-requiring-enzyme 1 (ire-1) and the protein kinase RNA-like endoplasmic reticulum kinase (pek-1) branches of the (UPR-ER). Interestingly, activation of the (UPR-ER) output gene heat shock protein 4 (hsp-4) was partially independent of its canonical activators, ire-1 and X-box binding protein (xbp-1), and instead required the third branch of the (UPR-ER), activating transcription factor 6 (atf-6), suggesting functional redundancy. We further found that primase depletion specifically induces the (UPR-ER), but not the distinct cytosolic or mitochondrial UPRs, suggesting that primase inactivation causes compartment-specific rather than global stress. Functionally, loss of ire-1 or pek-1 sensitizes animals to replication stress caused by hydroxyurea. Finally, transcriptome analysis of pri-1 embryos revealed several deregulated processes that could cause (UPR-ER) activation, including protein glycosylation, calcium signaling, and fatty acid desaturation. Together, our data show that the (UPR-ER), but not other UPRs, responds to replication fork stress and that the (UPR-ER) is required to alleviate this stress.
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Affiliation(s)
- Jiaming Xu
- Graduate Program in Cell & Developmental Biology, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- Centre for Molecular Medicine and Therapeutics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- British Columbia Children’s Hospital Research Institute, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
| | - Brendil Sabatino
- Centre for Molecular Medicine and Therapeutics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- British Columbia Children’s Hospital Research Institute, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- Department of Medical Genetics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
| | - Junran Yan
- Centre for Molecular Medicine and Therapeutics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- British Columbia Children’s Hospital Research Institute, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- Edwin S.H. Leong Centre for Healthy Aging, The University of British Columbia, 117-2194 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Medical Genetics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
| | - Glafira Ermakova
- Centre for Molecular Medicine and Therapeutics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- British Columbia Children’s Hospital Research Institute, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- Edwin S.H. Leong Centre for Healthy Aging, The University of British Columbia, 117-2194 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Medical Genetics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
| | - Kelsie R S Doering
- Centre for Molecular Medicine and Therapeutics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- British Columbia Children’s Hospital Research Institute, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- Edwin S.H. Leong Centre for Healthy Aging, The University of British Columbia, 117-2194 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Medical Genetics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
| | - Stefan Taubert
- Graduate Program in Cell & Developmental Biology, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- Centre for Molecular Medicine and Therapeutics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- British Columbia Children’s Hospital Research Institute, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
- Edwin S.H. Leong Centre for Healthy Aging, The University of British Columbia, 117-2194 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Medical Genetics, The University of British Columbia, 950 W 28th Ave, Vancouver, BC V5Z 4H4, Canada
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10
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Le Goupil S, Laprade H, Aubry M, Chevet E. Exploring the IRE1 interactome: From canonical signaling functions to unexpected roles. J Biol Chem 2024; 300:107169. [PMID: 38494075 PMCID: PMC11007444 DOI: 10.1016/j.jbc.2024.107169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 03/04/2024] [Accepted: 03/08/2024] [Indexed: 03/19/2024] Open
Abstract
The unfolded protein response is a mechanism aiming at restoring endoplasmic reticulum (ER) homeostasis and is likely involved in other adaptive pathways. The unfolded protein response is transduced by three proteins acting as sensors and triggering downstream signaling pathways. Among them, inositol-requiring enzyme 1 alpha (IRE1α) (referred to as IRE1 hereafter), an endoplasmic reticulum-resident type I transmembrane protein, exerts its function through both kinase and endoribonuclease activities, resulting in both X-box binding protein 1 mRNA splicing and RNA degradation (regulated ire1 dependent decay). An increasing number of studies have reported protein-protein interactions as regulators of these signaling mechanisms, and additionally, driving other noncanonical functions. In this review, we deliver evolutive and structural insights on IRE1 and further describe how this protein interaction network (interactome) regulates IRE1 signaling abilities or mediates other cellular processes through catalytic-independent mechanisms. Moreover, we focus on newly discovered targets of IRE1 kinase activity and discuss potentially novel IRE1 functions based on the nature of the interactome, thereby identifying new fields to explore regarding this protein's biological roles.
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Affiliation(s)
- Simon Le Goupil
- INSERM U1242, University of Rennes, Rennes, France; Centre de Lutte contre le cancer Eugène Marquis, Rennes, France.
| | - Hadrien Laprade
- INSERM U1242, University of Rennes, Rennes, France; Centre de Lutte contre le cancer Eugène Marquis, Rennes, France
| | - Marc Aubry
- INSERM U1242, University of Rennes, Rennes, France; Centre de Lutte contre le cancer Eugène Marquis, Rennes, France
| | - Eric Chevet
- INSERM U1242, University of Rennes, Rennes, France; Centre de Lutte contre le cancer Eugène Marquis, Rennes, France
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11
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Duan Z, Chen K, Yang T, You R, Chen B, Li J, Liu L. Mechanisms of Endoplasmic Reticulum Protein Homeostasis in Plants. Int J Mol Sci 2023; 24:17599. [PMID: 38139432 PMCID: PMC10743519 DOI: 10.3390/ijms242417599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 12/24/2023] Open
Abstract
Maintenance of proteome integrity is essential for cell function and survival in changing cellular and environmental conditions. The endoplasmic reticulum (ER) is the major site for the synthesis of secretory and membrane proteins. However, the accumulation of unfolded or misfolded proteins can perturb ER protein homeostasis, leading to ER stress and compromising cellular function. Eukaryotic organisms have evolved sophisticated and conserved protein quality control systems to ensure protein folding fidelity via the unfolded protein response (UPR) and to eliminate potentially harmful proteins via ER-associated degradation (ERAD) and ER-phagy. In this review, we summarize recent advances in our understanding of the mechanisms of ER protein homeostasis in plants and discuss the crosstalk between different quality control systems. Finally, we will address unanswered questions in this field.
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Affiliation(s)
- Zhihao Duan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Kai Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Tao Yang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Ronghui You
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Binzhao Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Jianming Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
- Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong
| | - Linchuan Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
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12
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Liu H, Xu L, Zhang Y, Xie Y, Wang L, Zhou Y, Wang Z, Pan Y, Li W, Xu L, Xu X, Wang T, Meng K, He J, Qiu Y, Xu G, Ge W, Zhu Y, Wang L. Copper Increases the Sensitivity of Cholangiocarcinoma Cells to Tripterine by Inhibiting TMX2-Mediated Unfolded Protein Reaction Activation. Adv Healthc Mater 2023; 12:e2300913. [PMID: 37119498 DOI: 10.1002/adhm.202300913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 04/18/2023] [Indexed: 05/01/2023]
Abstract
Chemotherapy-induced adaptive resistance is a significant factor that contributes to low therapeutic efficacy in tumor cells. The unfolded protein response (UPR) is a key mechanism in the development of drug resistance and serves as a critical reactive system for endoplasmic reticulum stress. Cu(II) can reduce the abundance of 60S ribosomal subunits and inhibit rRNA processing, leading to a decrease in the translation efficiency of the GRP78/BiP mRNA, which serves as a primary sensor for UPR activation. In this study, CuET-Lipid@Cela, composed of CuET and tripterine (Cela), demonstrates a significant synergistic antitumor effect on cholangiocarcinoma (CCA) cells. RNA-Seq is used to investigate the underlying mechanism, which suggests that the transmembrane protein 2 (TMX2) gene may be crucial in Cu(II) regulation of UPR by inhibiting the activation of GRP78/BiP and PERK/eIF2α. The synergistic antitumor efficacy of CuET-Lipid@Cela via inhibition of TMX2 is also confirmed in a myrAKT/YapS127A plasmid-induced primary CCA mouse model, providing new insights into the reversal of acquired chemotherapy-induced resistance in CCA.
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Affiliation(s)
- Hongwen Liu
- Department of Gastroenterology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, Jiangsu Province, 210008, P. R. China
| | - Lei Xu
- Department of Gastroenterology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, Jiangsu Province, 210008, P. R. China
| | - Yiyang Zhang
- Department of Gastroenterology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, Jiangsu Province, 210008, P. R. China
| | - Yiqiong Xie
- Department of Pharmacy, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, 21008, P. R. China
| | - Lishan Wang
- Department of Gastroenterology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, 21008, P. R. China
| | - Yue Zhou
- Department of Gastroenterology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, Jiangsu Province, 210008, P. R. China
| | - Zhangding Wang
- Department of Gastroenterology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, Jiangsu Province, 210008, P. R. China
| | - Yani Pan
- Department of Gastroenterology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, Jiangsu Province, 210008, P. R. China
| | - Wenying Li
- Department of Gastroenterology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, 21008, P. R. China
| | - Lu Xu
- Department of Pharmacy, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, 21008, P. R. China
| | - Xinyun Xu
- Department of Pathology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, Jiangsu Province, 210008, P. R. China
| | - Ting Wang
- Department of Pathology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, Jiangsu Province, 210008, P. R. China
| | - Kui Meng
- Department of Pathology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, Jiangsu Province, 210008, P. R. China
| | - Jian He
- Department of Nuclear Medicine, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, Jiangsu Province, 210008, P. R. China
| | - Yudong Qiu
- Department of Hepatopancreatobiliary Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, Jiangsu Province, 210008, P. R. China
| | - Guifang Xu
- Department of Gastroenterology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, Jiangsu Province, 210008, P. R. China
- Department of Gastroenterology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, 21008, P. R. China
| | - Weihong Ge
- Department of Pharmacy, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, 21008, P. R. China
- Nanjing Medical Center for Clinical Pharmacy, Nanjing, Jiangsu Province, 210008, P. R. China
| | - Yun Zhu
- Department of Gastroenterology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, Jiangsu Province, 210008, P. R. China
- Department of Pharmacy, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, 21008, P. R. China
- Nanjing Medical Center for Clinical Pharmacy, Nanjing, Jiangsu Province, 210008, P. R. China
| | - Lei Wang
- Department of Gastroenterology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, Jiangsu Province, 210008, P. R. China
- Department of Gastroenterology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, 21008, P. R. China
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13
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Zhao S, Feng H, Jiang D, Yang K, Wang ST, Zhang YX, Wang Y, Liu H, Guo C, Tang TS. ER Ca 2+ overload activates the IRE1α signaling and promotes cell survival. Cell Biosci 2023; 13:123. [PMID: 37400935 DOI: 10.1186/s13578-023-01062-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 05/26/2023] [Indexed: 07/05/2023] Open
Abstract
BACKGROUND Maintaining homeostasis of Ca2+ stores in the endoplasmic reticulum (ER) is crucial for proper Ca2+ signaling and key cellular functions. Although Ca2+ depletion has been known to cause ER stress which in turn activates the unfolded protein response (UPR), how UPR sensors/transducers respond to excess Ca2+ when ER stores are overloaded remain largely unclear. RESULTS Here, we report for the first time that overloading of ER Ca2+ can directly sensitize the IRE1α-XBP1 axis. The overloaded ER Ca2+ in TMCO1-deficient cells can cause BiP dissociation from IRE1α, promote the dimerization and stability of the IRE1α protein, and boost IRE1α activation. Intriguingly, attenuation of the over-activated IRE1α-XBP1s signaling by a IRE1α inhibitor can cause a significant cell death in TMCO1-deficient cells. CONCLUSIONS Our data establish a causal link between excess Ca2+ in ER stores and the selective activation of IRE1α-XBP1 axis, underscoring an unexpected role of overload of ER Ca2+ in IRE1α activation and in preventing cell death.
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Affiliation(s)
- Song Zhao
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Haiping Feng
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Dongfang Jiang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Keyan Yang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Si-Tong Wang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yu-Xin Zhang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yun Wang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Hongmei Liu
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101, China.
| | - Caixia Guo
- Beijing Institute of Genomics, Chinese Academy of Sciences/China National Center for Bioinformation, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Tie-Shan Tang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
- Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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14
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Ben-Khoud Y, Chen CS, Ali MMU. Alternative ATPase domain interactions in eukaryotic Hsp70 chaperones. Front Mol Biosci 2023; 10:1155784. [PMID: 37006606 PMCID: PMC10061150 DOI: 10.3389/fmolb.2023.1155784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/06/2023] [Indexed: 03/18/2023] Open
Abstract
Hsp70 molecular chaperones are essential components for maintaining protein homeostasis within cells. They interact with substrate or client proteins in a well characterised fashion that is regulated by ATP and supported by co-chaperones. In eukaryotes there is a vast array of Hsp70 isoforms that may facilitate adaption to a particular cellular compartment and distinct biological role. Emerging data indicate a novel type of interaction between Hsp70 and client protein that does not fit with the classical Hsp70 ATP regulated substrate mechanism. In this review, we highlight Hsp70 ATPase domain interactions with binding partners from various biological systems that we refer to as Hsp70 ATPase alternative binding proteins or HAAB proteins. We identify common mechanistic features that may define how Hsp70 operates when associating with proteins in this alternative HAAB mode of action.
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Affiliation(s)
- Yassin Ben-Khoud
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Chao-Sheng Chen
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Maruf M U Ali
- Department of Life Sciences, Imperial College London, London, United Kingdom
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15
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Kovaleva V, Yu LY, Ivanova L, Shpironok O, Nam J, Eesmaa A, Kumpula EP, Sakson S, Toots U, Ustav M, Huiskonen JT, Voutilainen MH, Lindholm P, Karelson M, Saarma M. MANF regulates neuronal survival and UPR through its ER-located receptor IRE1α. Cell Rep 2023; 42:112066. [PMID: 36739529 DOI: 10.1016/j.celrep.2023.112066] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 10/20/2022] [Accepted: 01/19/2023] [Indexed: 02/05/2023] Open
Abstract
Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an endoplasmic reticulum (ER)-located protein with cytoprotective effects in neurons and pancreatic β cells in vitro and in models of neurodegeneration and diabetes in vivo. However, the exact mode of MANF action has remained elusive. Here, we show that MANF directly interacts with the ER transmembrane unfolded protein response (UPR) sensor IRE1α, and we identify the binding interface between MANF and IRE1α. The expression of wild-type MANF, but not its IRE1α binding-deficient mutant, attenuates UPR signaling by decreasing IRE1α oligomerization; phosphorylation; splicing of Xbp1, Atf6, and Txnip levels; and protecting neurons from ER stress-induced death. MANF-IRE1α interaction and not MANF-BiP interaction is crucial for MANF pro-survival activity in neurons in vitro and is required to protect dopamine neurons in an animal model of Parkinson's disease. Our data show IRE1α as an intracellular receptor for MANF and regulator of neuronal survival.
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Affiliation(s)
- Vera Kovaleva
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland.
| | - Li-Ying Yu
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland
| | - Larisa Ivanova
- Institute of Chemistry, University of Tartu, 50411 Tartu, Estonia
| | - Olesya Shpironok
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland
| | - Jinhan Nam
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland; Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, 00014 Helsinki, Finland
| | - Ave Eesmaa
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland
| | - Esa-Pekka Kumpula
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland
| | - Sven Sakson
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland
| | | | | | - Juha T Huiskonen
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland
| | - Merja H Voutilainen
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland; Division of Pharmacology and Pharmacotherapy, Faculty of Pharmacy, University of Helsinki, 00014 Helsinki, Finland
| | - Päivi Lindholm
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland
| | - Mati Karelson
- Institute of Chemistry, University of Tartu, 50411 Tartu, Estonia
| | - Mart Saarma
- Institute of Biotechnology, HiLIFE, University of Helsinki, 00014 Helsinki, Finland.
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16
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Tiwari S, Fauvet B, Assenza S, De Los Rios P, Goloubinoff P. A fluorescent multi-domain protein reveals the unfolding mechanism of Hsp70. Nat Chem Biol 2023; 19:198-205. [PMID: 36266349 PMCID: PMC9889267 DOI: 10.1038/s41589-022-01162-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 09/06/2022] [Indexed: 02/04/2023]
Abstract
Detailed understanding of the mechanism by which Hsp70 chaperones protect cells against protein aggregation is hampered by the lack of a comprehensive characterization of the aggregates, which are typically heterogeneous. Here we designed a reporter chaperone substrate, MLucV, composed of a stress-labile luciferase flanked by stress-resistant fluorescent domains, which upon denaturation formed a discrete population of small aggregates. Combining Förster resonance energy transfer and enzymatic activity measurements provided unprecedented details on the aggregated, unfolded, Hsp70-bound and native MLucV conformations. The Hsp70 mechanism first involved ATP-fueled disaggregation and unfolding of the stable pre-aggregated substrate, which stretched MLucV beyond simply unfolded conformations, followed by native refolding. The ATP-fueled unfolding and refolding action of Hsp70 on MLucV aggregates could accumulate native MLucV species under elevated denaturing temperatures highly adverse to the native state. These results unambiguously exclude binding and preventing of aggregation from the non-equilibrium mechanism by which Hsp70 converts stable aggregates into metastable native proteins.
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Affiliation(s)
- Satyam Tiwari
- grid.9851.50000 0001 2165 4204Department of Plant Molecular Biology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland ,grid.5333.60000000121839049Institute of Physics, School of Basic Sciences, École Polytechnique Fédérale de Lausanne - EPFL, Lausanne, Switzerland
| | - Bruno Fauvet
- grid.5333.60000000121839049Institute of Physics, School of Basic Sciences, École Polytechnique Fédérale de Lausanne - EPFL, Lausanne, Switzerland
| | - Salvatore Assenza
- grid.5515.40000000119578126Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, Madrid, Spain ,grid.5515.40000000119578126Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Madrid, Spain ,grid.5515.40000000119578126Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, Madrid, Spain
| | - Paolo De Los Rios
- Institute of Physics, School of Basic Sciences, École Polytechnique Fédérale de Lausanne - EPFL, Lausanne, Switzerland. .,Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne - EPFL, Lausanne, Switzerland.
| | - Pierre Goloubinoff
- Department of Plant Molecular Biology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland. .,School of Plant Sciences and Food Security, Tel-Aviv University, Tel Aviv, Israel.
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17
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Benske TM, Mu TW, Wang YJ. Protein quality control of N-methyl-D-aspartate receptors. Front Cell Neurosci 2022; 16:907560. [PMID: 35936491 PMCID: PMC9352929 DOI: 10.3389/fncel.2022.907560] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 06/29/2022] [Indexed: 12/23/2022] Open
Abstract
N-methyl-D-aspartate receptors (NMDARs) are glutamate-gated cation channels that mediate excitatory neurotransmission and are critical for synaptic development and plasticity in the mammalian central nervous system (CNS). Functional NMDARs typically form via the heterotetrameric assembly of GluN1 and GluN2 subunits. Variants within GRIN genes are implicated in various neurodevelopmental and neuropsychiatric disorders. Due to the significance of NMDAR subunit composition for regional and developmental signaling at synapses, properly folded receptors must reach the plasma membrane for their function. This review focuses on the protein quality control of NMDARs. Specifically, we review the quality control mechanisms that ensure receptors are correctly folded and assembled within the endoplasmic reticulum (ER) and trafficked to the plasma membrane. Further, we discuss disease-associated variants that have shown disrupted NMDAR surface expression and function. Finally, we discuss potential targeted pharmacological and therapeutic approaches to ameliorate disease phenotypes by enhancing the expression and surface trafficking of subunits harboring disease-associated variants, thereby increasing their incorporation into functional receptors.
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Affiliation(s)
| | - Ting-Wei Mu
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Ya-Juan Wang
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
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18
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Regulation of calcium homeostasis and flux between the endoplasmic reticulum and the cytosol. J Biol Chem 2022; 298:102061. [PMID: 35609712 PMCID: PMC9218512 DOI: 10.1016/j.jbc.2022.102061] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 12/20/2022] Open
Abstract
The concentration of Ca2+ in the endoplasmic reticulum (ER) is critically important for maintaining its oxidizing environment as well as for maintaining luminal ATP levels required for chaperone activity. Therefore, local luminal Ca2+ concentrations and the dynamic Ca2+ flux between the different subcellular compartments are tightly controlled. Influx of Ca2+ into the ER is enabled by a reductive shift, which opens the sarcoendoplasmic reticulum calcium transport ATPase pump, building the Ca2+ gradient across the ER membrane required for ATP import. Meanwhile, Ca2+ leakage from the ER has been reported to occur via the Sec61 translocon following protein translocation. In this review, we provide an overview of the complex regulation of Ca2+ homeostasis, Ca2+ flux between subcellular compartments, and the cellular stress response (the unfolded protein response) induced upon dysregulated luminal Ca2+ metabolism. We also provide insight into the structure and gating mechanism at the Sec61 translocon and examine the role of ER-resident cochaperones in assisting the central ER-resident chaperone BiP in the control of luminal Ca2+ concentrations.
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19
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Yu CY, Cho Y, Sharma O, Kanehara K. What's unique? The unfolded protein response in plants. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:1268-1276. [PMID: 34849719 DOI: 10.1093/jxb/erab513] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 11/22/2021] [Indexed: 06/13/2023]
Abstract
The investigation of a phenomenon called the unfolded protein response (UPR) started approximately three decades ago, and we now know that the UPR is involved in a number of cellular events among metazoans, higher plants, and algae. The relevance of the UPR in human diseases featuring protein folding defects, such as Alzheimer's and Huntington's diseases, has drawn much attention to the response in medical research to date. While metazoans and plants share similar molecular mechanisms of the UPR, recent studies shed light on the uniqueness of the plant UPR, with plant-specific protein families appearing to play pivotal roles. Given the considerable emphasis on the original discoveries of key factors in metazoans, this review highlights the uniqueness of the plant UPR based on current knowledge.
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Affiliation(s)
- Chao-Yuan Yu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Yueh Cho
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Oshin Sharma
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Kazue Kanehara
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan
- Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
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20
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Maity S, Komal P, Kumar V, Saxena A, Tungekar A, Chandrasekar V. Impact of ER Stress and ER-Mitochondrial Crosstalk in Huntington's Disease. Int J Mol Sci 2022; 23:780. [PMID: 35054963 PMCID: PMC8775980 DOI: 10.3390/ijms23020780] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/30/2021] [Accepted: 01/03/2022] [Indexed: 02/07/2023] Open
Abstract
Accumulation of misfolded proteins is a common phenomenon of several neurodegenerative diseases. The misfolding of proteins due to abnormal polyglutamine (PolyQ) expansions are linked to the development of PolyQ diseases including Huntington's disease (HD). Though the genetic basis of PolyQ repeats in HD remains prominent, the primary molecular basis mediated by PolyQ toxicity remains elusive. Accumulation of misfolded proteins in the ER or disruption of ER homeostasis causes ER stress and activates an evolutionarily conserved pathway called Unfolded protein response (UPR). Protein homeostasis disruption at organelle level involving UPR or ER stress response pathways are found to be linked to HD. Due to dynamic intricate connections between ER and mitochondria, proteins at ER-mitochondria contact sites (mitochondria associated ER membranes or MAMs) play a significant role in HD development. The current review aims at highlighting the most updated information about different UPR pathways and their involvement in HD disease progression. Moreover, the role of MAMs in HD progression has also been discussed. In the end, the review has focused on the therapeutic interventions responsible for ameliorating diseased states via modulating either ER stress response proteins or modulating the expression of ER-mitochondrial contact proteins.
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Affiliation(s)
- Shuvadeep Maity
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS)-Pilani (Hyderabad Campus), Shameerpet-Mandal, Hyderabad 500078, Telangana, India; (P.K.); (V.K.); (A.S.); (A.T.); (V.C.)
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21
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Zhou Z, Wang Q, Michalak M. Inositol Requiring Enzyme (IRE), a multiplayer in sensing endoplasmic reticulum stress. Anim Cells Syst (Seoul) 2022; 25:347-357. [PMID: 35059134 PMCID: PMC8765250 DOI: 10.1080/19768354.2021.2020901] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Affiliation(s)
- Zhixin Zhou
- Department of Biochemistry, University of Alberta, Edmonton, Canada
| | - Qian Wang
- Department of Biochemistry, University of Alberta, Edmonton, Canada
| | - Marek Michalak
- Department of Biochemistry, University of Alberta, Edmonton, Canada
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22
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The Unfolded Protein Response as a Guardian of the Secretory Pathway. Cells 2021; 10:cells10112965. [PMID: 34831188 PMCID: PMC8616143 DOI: 10.3390/cells10112965] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 10/27/2021] [Accepted: 10/29/2021] [Indexed: 02/07/2023] Open
Abstract
The endoplasmic reticulum (ER) is the major site of membrane biogenesis in most eukaryotic cells. As the entry point to the secretory pathway, it handles more than 10,000 different secretory and membrane proteins. The insertion of proteins into the membrane, their folding, and ER exit are affected by the lipid composition of the ER membrane and its collective membrane stiffness. The ER is also a hotspot of lipid biosynthesis including sterols, glycerophospholipids, ceramides and neural storage lipids. The unfolded protein response (UPR) bears an evolutionary conserved, dual sensitivity to both protein-folding imbalances in the ER lumen and aberrant compositions of the ER membrane, referred to as lipid bilayer stress (LBS). Through transcriptional and non-transcriptional mechanisms, the UPR upregulates the protein folding capacity of the ER and balances the production of proteins and lipids to maintain a functional secretory pathway. In this review, we discuss how UPR transducers sense unfolded proteins and LBS with a particular focus on their role as guardians of the secretory pathway.
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23
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Paeoniflorin Effect of Schwann Cell-Derived Exosomes Ameliorates Dorsal Root Ganglion Neurons Apoptosis through IRE1 α Pathway. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2021; 2021:6079305. [PMID: 34616478 PMCID: PMC8490051 DOI: 10.1155/2021/6079305] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/20/2021] [Indexed: 02/06/2023]
Abstract
Background Diabetic peripheral neuropathy (DPN) is a common complication of diabetes but its pathogenesis is not fully clarified. Endoplasmic reticulum (ER) stress has been confirmed to be involved in the development of DPN. Dorsal root ganglion neuron (DRGn) is the target cell of DPN injure in the peripheral neurons system. Schwann cell (SCs)-derived exosomes (SC-EXOs) can carry IRE1α signal transduction factors in ER stress to DRGn. The aim of this study is to investigate the effect of SC-EXOs treated with paeoniflorin (PF) on DRGn stimulated by high glucose. Methods SCs were divided into Control group (Control), 150 mM glucose group (HG), high osmotic pressure group (HOP), and low, middle, and high dose PF group (PF1, PF10, and PF100). Exosomes were obtained from SCs by ultracentrifugation and identified according to marker proteins, including CD63, Alix, Hsp70, and TSG101. ER stress initiating factor GRP78, the IRE1α pathway information transmission factor IRE1α, and the phosphorylation level of IRE1α were detected by Western blot, DRGn is divided into Control group (Control), 50 mM glucose group + Control exosomes group (HG + EXOs Control), 50 mM glucose group (HG), and 50 mM glucose group + administration exosomes group (HG + EXOs PF1, HG + EXOs PF10, and HG + EXOs PF100); ER morphology of primary DRGn was observed by using the transmission electron microscope, the level of DRGn apoptosis was analyzed by TUNEL, and the downstream proteins of ER stress including CHOP, XBP1S, JNK, and p-JNK in DRG and the expression of apoptosis-related proteins Bcl-2, Bax, Caspase-3, and Caspase-12 were measured by Western blot. Results Compared with the exosomes in the HG group, the exosomes after the intervention of PF can significantly reduce the expression of GRP78, IRE1α, and the phosphorylation level of IRE1α(P < 0.05); compared with the DRGn in the HG group, the SC-EXOs treated with PF could regulate the expression of proteins downstream of IRE1α pathway in ER stress (P < 0.05 or P < 0.01), improve the morphological integrity of ER, and reduce apoptosis in DRGn (P < 0.05 or P < 0.01). Conclusion PF regulates the information of ER stress carried by SC-EXOs and further affects downstream of IRE1α pathway in DRGn, thus reducing ER stress-induced apoptosis. PF can interfere with DPN through affecting information communication carried by EXOs between SCs and DRGn.
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24
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Gao J, Liu Y, Ji J, Liu Z. [Heat stress induces neuronal apoptosis by up-regulating endoplasmic reticulum stress pathway]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2021; 41:702-709. [PMID: 34134957 DOI: 10.12122/j.issn.1673-4254.2021.05.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To explore the role of endoplasmic reticulum stress in heat stress-induced apoptosis of human neuroblastoma SH-SY5Y cells. OBJECTIVE SH-SY5Y cells were incubated at 43 ℃ for 2 h followed by further culture at 37 ℃ for 0, 3 h, or 6 h. With the cells cultured at 37 ℃ as the control, the cells exposed to heat stress were examined for morphological changes under optical microscope and changes in cell viability using CCK-8 assay. Flow cytometry was performed for detecting apoptosis of the cells following heat stress, and intracellular Ca2+ level in the cells was determined using flow cytometry and immunofluorescence confocal microscopy. The mRNA expression levels of caspase-12, BIP and XBP-1 in the cells were detected using qRT-PCR, and the protein expressions of caspase-12, BIP, P-JNK, JNK and XBP-1 were examined using Western blotting. The effect of pretreatment with 4-PBA on cell apoptosis following heat stress was analyzed with Western blotting. OBJECTIVE SH-SY5Y cells showed obvious cell shrinkage immediately after the exposure to heat stress, followed then by gradual cell stretching over time. The cell viability decreased significantly after heat stress (P=0.001), and the intracellular Ca2+ level increased significantly at 0 h and gradually recovered the normal level at 3 and 6 h. Heat stress induced significant increase in the protein expression of cleaved caspase-3 and time-dependent increase of caspase-12 (P=0.002) and BIP (P=0.008) expression at both the protein and mRNA levels. The expression of P-JNK/JNK protein increased significantly at 0 h (P=0.003) followed by gradual decrease; the expression levels of XBP-1 protein and mRNA gradually decreased after heat stress (P=0.005, P=0.002). Pretreatment with 4-PBA significantly reduced the expression level of cleaved caspase-3 in SH-SY5Y cells following heat stress. OBJECTIVE Heat stress induces apoptosis of SH-SY5Y cells by triggering endoplasmic reticulum stress and the imbalance of intracellular calcium ion homeostasis.
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Affiliation(s)
- J Gao
- First College of Clinical Medicine, Southern Medical University, Guangzhou 510515, China.,Department of Critical Care Medicine, General Hospital of Southern Theatre Command of PLA, Guangzhou 510010, China
| | - Y Liu
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - J Ji
- Department of Critical Care Medicine, General Hospital of Southern Theatre Command of PLA, Guangzhou 510010, China
| | - Z Liu
- First College of Clinical Medicine, Southern Medical University, Guangzhou 510515, China.,Department of Critical Care Medicine, General Hospital of Southern Theatre Command of PLA, Guangzhou 510010, China
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25
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Han SJ, Noh M, Jang J, Lee JB, Kim KS. Electric fields regulate cellular elasticity through intracellular Ca 2+ concentrations. J Cell Physiol 2021; 236:7450-7463. [PMID: 33993476 DOI: 10.1002/jcp.30417] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 04/25/2021] [Accepted: 04/28/2021] [Indexed: 11/06/2022]
Abstract
Cellular elasticity is a key factor related to a broad range of physiological and pathological processes. The elasticity of a single cell has thus emerged as a potential biomarker to characterize the cellular state. Both internal and external stimuli affect cellular elasticity, and changes in elasticity can cause alterations in cellular characteristics or function. The application of electric fields (EFs) is a promising method that can be used to change cellular elasticity; however, the mechanisms underlying its effect remain unknown. Here, we demonstrate EFs-induced elasticity changes in human dermal fibroblasts and discuss the underlying mechanism related to actin polymerization. Cellular elasticity increases after EF (50 mV/mm) stimulation, reaching a maximum at 30 min before decreasing between 30 and 120 min. The cellular elasticity under EF stimulation, regardless of stimulation time, is higher than that of the control. F-actin regulates the elasticity of cells through gelsolin activation. We show changes in intracellular Ca2+ caused by EFs, which induced gelsolin activation and F-actin content changes. This result demonstrates a series of processes in which external electrical stimulation conditions regulate cellular elasticity.
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Affiliation(s)
- Se Jik Han
- Department of Biomedical Engineering, Graduate School, Kyung Hee University, Seoul, Korea.,Department of Biomedical Engineering, Kyung Hee University, Seoul, Korea
| | - Minjoo Noh
- Innovation Lab, Department of Innovation, Cosmax R&I Center, Gyeonggi do, Korea
| | - Jihui Jang
- Innovation Lab, Department of Innovation, Cosmax R&I Center, Gyeonggi do, Korea
| | - Jun Bae Lee
- Innovation Lab, Department of Innovation, Cosmax R&I Center, Gyeonggi do, Korea
| | - Kyung Sook Kim
- Department of Biomedical Engineering, Kyung Hee University, Seoul, Korea
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26
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The Structure, Activation and Signaling of IRE1 and Its Role in Determining Cell Fate. Biomedicines 2021; 9:biomedicines9020156. [PMID: 33562589 PMCID: PMC7914947 DOI: 10.3390/biomedicines9020156] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/22/2021] [Accepted: 02/02/2021] [Indexed: 02/06/2023] Open
Abstract
Inositol-requiring enzyme type 1 (IRE1) is a serine/threonine kinase acting as one of three branches of the Unfolded Protein Response (UPR) signaling pathway, which is activated upon endoplasmic reticulum (ER) stress conditions. It is known to be capable of inducing both pro-survival and pro-apoptotic cellular responses, which are strictly related to numerous human pathologies. Among others, IRE1 activity has been confirmed to be increased in cancer, neurodegeneration, inflammatory and metabolic disorders, which are associated with an accumulation of misfolded proteins within ER lumen and the resulting ER stress conditions. Emerging evidence suggests that genetic or pharmacological modulation of IRE1 may have a significant impact on cell viability, and thus may be a promising step forward towards development of novel therapeutic strategies. In this review, we extensively describe the structural analysis of IRE1 molecule, the molecular dynamics associated with IRE1 activation, and interconnection between it and the other branches of the UPR with regard to its potential use as a therapeutic target. Detailed knowledge of the molecular characteristics of the IRE1 protein and its activation may allow the design of specific kinase or RNase modulators that may act as drug candidates.
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27
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Intestinal Immune Homeostasis and Inflammatory Bowel Disease: A Perspective on Intracellular Response Mechanisms. GASTROINTESTINAL DISORDERS 2020. [DOI: 10.3390/gidisord2030024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The pathogenesis of inflammatory bowel disease (IBD) involves perturbation of intestinal immune homeostasis in genetically susceptible individuals. A mutual interplay between intestinal epithelial cells (IECs) and gut resident microbes maintains a homeostatic environment across the gut. An idiopathic gastrointestinal (GI) complication triggers aberrant physiological stress in the epithelium and peripheral myeloid cells, leading to a chronic inflammatory condition. Indeed, events in the endoplasmic reticulum (ER) and mitochondria contribute to orchestrating intracellular mechanisms such as the unfolded protein response (UPR) and oxidative stress, respectively, to resolve aberrant cellular stress. This review highlights the signaling cascades encrypted within ER and mitochondria in IECs and/or myeloid cells to dissipate chronic stress in maintaining intestinal homeostasis.
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28
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Urra H, Pihán P, Hetz C. The UPRosome - decoding novel biological outputs of IRE1α function. J Cell Sci 2020; 133:133/15/jcs218107. [PMID: 32788208 DOI: 10.1242/jcs.218107] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Different perturbations alter the function of the endoplasmic reticulum (ER), resulting in the accumulation of misfolded proteins in its lumen, a condition termed ER stress. To restore ER proteostasis, a highly conserved pathway is engaged, known as the unfolded protein response (UPR), triggering adaptive programs or apoptosis of terminally damaged cells. IRE1α (also known as ERN1), the most conserved UPR sensor, mediates the activation of responses to determine cell fate under ER stress. The complexity of IRE1α regulation and its signaling outputs is mediated in part by the assembly of a dynamic multi-protein complex, named the UPRosome, that regulates IRE1α activity and the crosstalk with other pathways. We discuss several studies identifying components of the UPRosome that have illuminated novel functions in cell death, autophagy, DNA damage, energy metabolism and cytoskeleton dynamics. Here, we provide a theoretical analysis to assess the biological significance of the UPRosome and present the results of a systematic bioinformatics analysis of the available IRE1α interactome data sets followed by functional enrichment clustering. This in silico approach decoded that IRE1α also interacts with proteins involved in the cell cycle, transport, differentiation, response to viral infection and immune response. Thus, defining the spectrum of IRE1α-binding partners will reveal novel signaling outputs and the relevance of the pathway to human diseases.
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Affiliation(s)
- Hery Urra
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile, Santiago 8380453, Chile .,Center for Geroscience, Brain Health and Metabolism (GERO), Santiago 7800003, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), University of Chile, Santiago 8380453, Chile
| | - Philippe Pihán
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile, Santiago 8380453, Chile.,Center for Geroscience, Brain Health and Metabolism (GERO), Santiago 7800003, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), University of Chile, Santiago 8380453, Chile
| | - Claudio Hetz
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile, Santiago 8380453, Chile .,Center for Geroscience, Brain Health and Metabolism (GERO), Santiago 7800003, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), University of Chile, Santiago 8380453, Chile.,The Buck Institute for Research in Aging, Novato, CA 94945, USA
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29
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Larburu N, Adams CJ, Chen CS, Nowak PR, Ali MMU. Mechanism of Hsp70 specialized interactions in protein translocation and the unfolded protein response. Open Biol 2020; 10:200089. [PMID: 32810420 PMCID: PMC7479934 DOI: 10.1098/rsob.200089] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 07/07/2020] [Indexed: 01/17/2023] Open
Abstract
Hsp70 chaperones interact with substrate proteins in a coordinated fashion that is regulated by nucleotides and enhanced by assisting cochaperones. There are numerous homologues and isoforms of Hsp70 that participate in a wide variety of cellular functions. This diversity can facilitate adaption or specialization based on particular biological activity and location within the cell. In this review, we highlight two specialized binding partner proteins, Tim44 and IRE1, that interact with Hsp70 at the membrane in order to serve their respective roles in protein translocation and unfolded protein response signalling. Recent mechanistic data suggest analogy in the way the two Hsp70 homologues (BiP and mtHsp70) can bind and release from IRE1 and Tim44 upon substrate engagement. These shared mechanistic features may underlie how Hsp70 interacts with specialized binding partners and may extend our understanding of the mechanistic repertoire that Hsp70 chaperones possess.
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Affiliation(s)
| | | | | | | | - Maruf M. U. Ali
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London SW7 2AZ, UK
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30
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Hetz C, Zhang K, Kaufman RJ. Mechanisms, regulation and functions of the unfolded protein response. Nat Rev Mol Cell Biol 2020; 21:421-438. [PMID: 32457508 DOI: 10.1038/s41580-020-0250-z] [Citation(s) in RCA: 1544] [Impact Index Per Article: 308.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2020] [Indexed: 12/21/2022]
Abstract
Cellular stress induced by the abnormal accumulation of unfolded or misfolded proteins at the endoplasmic reticulum (ER) is emerging as a possible driver of human diseases, including cancer, diabetes, obesity and neurodegeneration. ER proteostasis surveillance is mediated by the unfolded protein response (UPR), a signal transduction pathway that senses the fidelity of protein folding in the ER lumen. The UPR transmits information about protein folding status to the nucleus and cytosol to adjust the protein folding capacity of the cell or, in the event of chronic damage, induce apoptotic cell death. Recent advances in the understanding of the regulation of UPR signalling and its implications in the pathophysiology of disease might open new therapeutic avenues.
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Affiliation(s)
- Claudio Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile. .,FONDAP Center for Geroscience Brain Health and Metabolism (GERO), Santiago, Chile. .,Program of Cellular and Molecular Biology, Institute of Biomedical Science, University of Chile, Santiago, Chile. .,Buck Institute for Research on Aging, Novato, CA, USA.
| | - Kezhong Zhang
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI, USA. .,Department of Biochemistry, Microbiology and Immunology, Wayne State University School of Medicine, Detroit, MI, USA.
| | - Randal J Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.
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31
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Lenghel A, Gheorghita AM, Vacaru AM, Vacaru AM. What Is the Sweetest UPR Flavor for the β-cell? That Is the Question. Front Endocrinol (Lausanne) 2020; 11:614123. [PMID: 33613449 PMCID: PMC7891099 DOI: 10.3389/fendo.2020.614123] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 11/24/2020] [Indexed: 01/01/2023] Open
Abstract
Unfolded protein response (UPR) is a process conserved from yeasts to mammals and, based on the generally accepted dogma, helps the secretory performance of a cell, by improving its capacity to cope with a burden in the endoplasmic reticulum (ER). The ER of β-cells, "professional secretory cells", has to manage tremendous amounts of insulin, which elicits a strong pressure on the ER intrinsic folding capacity. Thus, the constant demand for insulin production results in misfolded proinsulin, triggering a physiological upregulation of UPR to restore homeostasis. Most diabetic disorders are characterized by the loss of functional β-cells, and the pathological side of UPR plays an instrumental role. The transition from a homeostatic to a pathological UPR that ultimately leads to insulin-producing β-cell decay entails complex cellular processes and molecular mechanisms which remain poorly described so far. Here, we summarize important processes that are coupled with or driven by UPR in β-cells, such as proliferation, inflammation and dedifferentiation. We conclude that the UPR comes in different "flavors" and each of them is correlated with a specific outcome for the cell, for survival, differentiation, proliferation as well as cell death. All these greatly depend on the way UPR is triggered, however what exactly is the switch that favors the activation of one UPR as opposed to others is largely unknown. Substantial work needs to be done to progress the knowledge in this important emerging field as this will help in the development of novel and more efficient therapies for diabetes.
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32
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Amin-Wetzel N, Neidhardt L, Yan Y, Mayer MP, Ron D. Unstructured regions in IRE1α specify BiP-mediated destabilisation of the luminal domain dimer and repression of the UPR. eLife 2019; 8:50793. [PMID: 31873072 PMCID: PMC6996924 DOI: 10.7554/elife.50793] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 12/23/2019] [Indexed: 12/15/2022] Open
Abstract
Coupling of endoplasmic reticulum (ER) stress to dimerisation-dependent activation of the UPR transducer IRE1 is incompletely understood. Whilst the luminal co-chaperone ERdj4 promotes a complex between the Hsp70 BiP and IRE1's stress-sensing luminal domain (IRE1LD) that favours the latter's monomeric inactive state and loss of ERdj4 de-represses IRE1, evidence linking these cellular and in vitro observations is presently lacking. We report that enforced loading of endogenous BiP onto endogenous IRE1α repressed UPR signalling in CHO cells and deletions in the IRE1α locus that de-repressed the UPR in cells, encode flexible regions of IRE1LD that mediated BiP-induced monomerisation in vitro. Changes in the hydrogen exchange mass spectrometry profile of IRE1LD induced by ERdj4 and BiP confirmed monomerisation and were consistent with active destabilisation of the IRE1LD dimer. Together, these observations support a competition model whereby waning ER stress passively partitions ERdj4 and BiP to IRE1LD to initiate active repression of UPR signalling.
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Affiliation(s)
- Niko Amin-Wetzel
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
| | - Lisa Neidhardt
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
| | - Yahui Yan
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
| | - Matthias P Mayer
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - David Ron
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
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33
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Kopp MC, Larburu N, Durairaj V, Adams CJ, Ali MMU. UPR proteins IRE1 and PERK switch BiP from chaperone to ER stress sensor. Nat Struct Mol Biol 2019; 26:1053-1062. [PMID: 31695187 PMCID: PMC6858872 DOI: 10.1038/s41594-019-0324-9] [Citation(s) in RCA: 254] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/01/2019] [Indexed: 12/24/2022]
Abstract
BiP is a major endoplasmic reticulum (ER) chaperone and is suggested to act as primary sensor in the activation of the unfolded protein response (UPR). How BiP operates as a molecular chaperone and as an ER stress sensor is unknown. Here, by reconstituting components of human UPR, ER stress and BiP chaperone systems, we discover that the interaction of BiP with the luminal domains of UPR proteins IRE1 and PERK switch BiP from its chaperone cycle into an ER stress sensor cycle by preventing the binding of its co-chaperones, with loss of ATPase stimulation. Furthermore, misfolded protein-dependent dissociation of BiP from IRE1 is primed by ATP but not ADP. Our data elucidate a previously unidentified mechanistic cycle of BiP function that explains its ability to act as an Hsp70 chaperone and ER stress sensor.
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Affiliation(s)
- Megan C Kopp
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London, UK
| | - Natacha Larburu
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London, UK
| | - Vinoth Durairaj
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London, UK
| | - Christopher J Adams
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London, UK
| | - Maruf M U Ali
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, London, UK.
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34
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Karagöz GE, Acosta-Alvear D, Walter P. The Unfolded Protein Response: Detecting and Responding to Fluctuations in the Protein-Folding Capacity of the Endoplasmic Reticulum. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a033886. [PMID: 30670466 DOI: 10.1101/cshperspect.a033886] [Citation(s) in RCA: 204] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Most of the secreted and plasma membrane proteins are synthesized on membrane-bound ribosomes on the endoplasmic reticulum (ER). They require engagement of ER-resident chaperones and foldases that assist in their folding and maturation. Since protein homeostasis in the ER is crucial for cellular function, the protein-folding status in the organelle's lumen is continually surveyed by a network of signaling pathways, collectively called the unfolded protein response (UPR). Protein-folding imbalances, or "ER stress," are detected by highly conserved sensors that adjust the ER's protein-folding capacity according to the physiological needs of the cell. We review recent developments in the field that have provided new insights into the ER stress-sensing mechanisms used by UPR sensors and the mechanisms by which they integrate various cellular inputs to adjust the folding capacity of the organelle to accommodate to fluctuations in ER protein-folding demands.
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Affiliation(s)
- G Elif Karagöz
- Howard Hughes Medical Institute and Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94143
| | - Diego Acosta-Alvear
- Department of Molecular, Cellular, and Developmental Biology, University of California at Santa Barbara, Santa Barbara, California 93106
| | - Peter Walter
- Howard Hughes Medical Institute and Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94143
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35
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Ricci D, Marrocco I, Blumenthal D, Dibos M, Eletto D, Vargas J, Boyle S, Iwamoto Y, Chomistek S, Paton JC, Paton AW, Argon Y. Clustering of IRE1α depends on sensing ER stress but not on its RNase activity. FASEB J 2019; 33:9811-9827. [PMID: 31199681 DOI: 10.1096/fj.201801240rr] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The sensors of the unfolded protein response react to endoplasmic reticulum (ER) stress by transient activation of their enzymatic activities, which initiate various signaling cascades. In addition, the sensor IRE1α exhibits stress-induced clustering in a transient time frame similar to activation of its endoRNase activity. Previous work had suggested that the clustering response and RNase activity of IRE1α are functionally linked, but here we show that they are independent of each other and have different behaviors and modes of activation. Although both clustering and the RNase activity are responsive to luminal stress conditions and to depletion of the ER chaperone binding protein, RNase-inactive IRE1α still clusters and, conversely, full RNase activity can be accomplished without clustering. The clusters formed by RNase-inactive IRE1α are much larger and persist longer than those induced by ER stress. Clustering requires autophosphorylation, and an IRE1α mutant whose RNase domain is responsive to ligands that bind the kinase domain forms yet a third type of stress-independent cluster, with distinct physical properties and half-lives. These data suggest that IRE1α clustering can follow distinct pathways upon activation of the sensor.-Ricci, D., Marrocco, I., Blumenthal, D., Dibos, M., Eletto, D., Vargas, J., Boyle, S., Iwamoto, Y., Chomistek, S., Paton, J. C., Paton, A. W., Argon, Y. Clustering of IRE1α depends on sensing ER stress but not on its RNase activity.
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Affiliation(s)
- Daniela Ricci
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ilaria Marrocco
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Daniel Blumenthal
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Miriam Dibos
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Daniela Eletto
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jade Vargas
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sarah Boyle
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yuichiro Iwamoto
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Steven Chomistek
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - James C Paton
- Department of Molecular and Cellular Biology, University of Adelaide, Adelaide, South Australia, Australia
| | - Adrienne W Paton
- Department of Molecular and Cellular Biology, University of Adelaide, Adelaide, South Australia, Australia
| | - Yair Argon
- Division of Cell Pathology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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36
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Abstract
Endoplasmic reticulum (ER) stress is a major contributor to liver disease and hepatic fibrosis, but the role it plays varies depending on the cause and progression of the disease. Furthermore, ER stress plays a distinct role in hepatocytes versus hepatic stellate cells (HSCs), which adds to the complexity of understanding ER stress and its downstream signaling through the unfolded protein response (UPR) in liver disease. Here, the authors focus on the current literature of ER stress in nonalcoholic and alcoholic fatty liver diseases, how ER stress impacts hepatocyte injury, and the role of ER stress in HSC activation and hepatic fibrosis. This review provides insight into the complex signaling and regulation of the UPR, parallels and distinctions between different liver diseases, and how ER stress may be targeted as an antisteatotic or antifibrotic therapy to limit the progression of liver disease.
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Affiliation(s)
- Jessica L. Maiers
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
| | - Harmeet Malhi
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota
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37
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Fun XH, Thibault G. Lipid bilayer stress and proteotoxic stress-induced unfolded protein response deploy divergent transcriptional and non-transcriptional programmes. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158449. [PMID: 31028913 DOI: 10.1016/j.bbalip.2019.04.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/14/2019] [Accepted: 04/22/2019] [Indexed: 12/13/2022]
Abstract
The unfolded protein response (UPR) is activated by endoplasmic reticulum (ER) stress and is designed to restore cellular homeostasis through multiple intracellular signalling pathways. In mammals, the UPR programme regulates the expression of hundreds of genes in response to signalling from ATF6, IRE1, and PERK. These three highly conserved stress sensors are activated by the accumulation of unfolded proteins within the ER. Alternatively, IRE1 and PERK sense generalised lipid bilayer stress (LBS) at the ER while ATF6 is activated by an increase of specific sphingolipids. As a result, the UPR supports cellular robustness as a broad-spectrum compensatory pathway that is achieved by deploying a tailored transcriptional programme adapted to the source of ER stress. This review summarises the current understanding of the three ER stress transducers in sensing proteotoxic stress and LBS. The plasticity of the UPR programme in the context of different sources of ER stress will also be discussed.
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Affiliation(s)
- Xiu Hui Fun
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Guillaume Thibault
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.
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38
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Adams CJ, Kopp MC, Larburu N, Nowak PR, Ali MMU. Structure and Molecular Mechanism of ER Stress Signaling by the Unfolded Protein Response Signal Activator IRE1. Front Mol Biosci 2019; 6:11. [PMID: 30931312 PMCID: PMC6423427 DOI: 10.3389/fmolb.2019.00011] [Citation(s) in RCA: 367] [Impact Index Per Article: 61.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 02/15/2019] [Indexed: 01/03/2023] Open
Abstract
The endoplasmic reticulum (ER) is an important site for protein folding and maturation in eukaryotes. The cellular requirement to synthesize proteins within the ER is matched by its folding capacity. However, the physiological demands or aberrations in folding may result in an imbalance which can lead to the accumulation of misfolded protein, also known as "ER stress." The unfolded protein response (UPR) is a cell-signaling system that readjusts ER folding capacity to restore protein homeostasis. The key UPR signal activator, IRE1, responds to stress by propagating the UPR signal from the ER to the cytosol. Here, we discuss the structural and molecular basis of IRE1 stress signaling, with particular focus on novel mechanistic advances. We draw a comparison between the recently proposed allosteric model for UPR induction and the role of Hsp70 during polypeptide import to the mitochondrial matrix.
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Affiliation(s)
| | | | | | | | - Maruf M. U. Ali
- Department of Life Sciences, Imperial College London, London, United Kingdom
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39
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Hiller S. Chaperone-Bound Clients: The Importance of Being Dynamic. Trends Biochem Sci 2019; 44:517-527. [PMID: 30611607 DOI: 10.1016/j.tibs.2018.12.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 11/29/2018] [Accepted: 12/11/2018] [Indexed: 01/14/2023]
Abstract
Several recent atomic-resolution studies have resolved how chaperones interact with their client proteins. In some cases, molecular chaperones recognize and bind their clients in conformational ensembles that are locally highly dynamic and interconvert, while in other cases clients bind in unique conformations. The presence of a locally dynamic client ensemble state has important consequences, both for the interpretation of experimental data and for the functionality of chaperones, as local dynamics facilitate rapid client release, folding on and from the chaperone surface, and client recognition without shape complementarity. Facilitated by the local dynamics, at least some chaperones appear to specifically recognize energetically frustrated sites of partially folded client proteins, such that the release of frustration contributes to the interaction affinity.
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40
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Almanza A, Carlesso A, Chintha C, Creedican S, Doultsinos D, Leuzzi B, Luís A, McCarthy N, Montibeller L, More S, Papaioannou A, Püschel F, Sassano ML, Skoko J, Agostinis P, de Belleroche J, Eriksson LA, Fulda S, Gorman AM, Healy S, Kozlov A, Muñoz‐Pinedo C, Rehm M, Chevet E, Samali A. Endoplasmic reticulum stress signalling - from basic mechanisms to clinical applications. FEBS J 2019; 286:241-278. [PMID: 30027602 PMCID: PMC7379631 DOI: 10.1111/febs.14608] [Citation(s) in RCA: 650] [Impact Index Per Article: 108.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 06/24/2018] [Accepted: 07/18/2018] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum (ER) is a membranous intracellular organelle and the first compartment of the secretory pathway. As such, the ER contributes to the production and folding of approximately one-third of cellular proteins, and is thus inextricably linked to the maintenance of cellular homeostasis and the fine balance between health and disease. Specific ER stress signalling pathways, collectively known as the unfolded protein response (UPR), are required for maintaining ER homeostasis. The UPR is triggered when ER protein folding capacity is overwhelmed by cellular demand and the UPR initially aims to restore ER homeostasis and normal cellular functions. However, if this fails, then the UPR triggers cell death. In this review, we provide a UPR signalling-centric view of ER functions, from the ER's discovery to the latest advancements in the understanding of ER and UPR biology. Our review provides a synthesis of intracellular ER signalling revolving around proteostasis and the UPR, its impact on other organelles and cellular behaviour, its multifaceted and dynamic response to stress and its role in physiology, before finally exploring the potential exploitation of this knowledge to tackle unresolved biological questions and address unmet biomedical needs. Thus, we provide an integrated and global view of existing literature on ER signalling pathways and their use for therapeutic purposes.
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Affiliation(s)
- Aitor Almanza
- Apoptosis Research CentreNational University of IrelandGalwayIreland
| | - Antonio Carlesso
- Department of Chemistry and Molecular BiologyUniversity of GothenburgGöteborgSweden
| | - Chetan Chintha
- Apoptosis Research CentreNational University of IrelandGalwayIreland
| | | | - Dimitrios Doultsinos
- INSERM U1242University of RennesFrance
- Centre de Lutte Contre le Cancer Eugène MarquisRennesFrance
| | - Brian Leuzzi
- Apoptosis Research CentreNational University of IrelandGalwayIreland
| | - Andreia Luís
- Ludwig Boltzmann Institute for Experimental and Clinical TraumatologyAUVA Research CentreViennaAustria
| | - Nicole McCarthy
- Institute for Experimental Cancer Research in PaediatricsGoethe‐UniversityFrankfurtGermany
| | - Luigi Montibeller
- Neurogenetics GroupDivision of Brain SciencesFaculty of MedicineImperial College LondonUK
| | - Sanket More
- Department Cellular and Molecular MedicineLaboratory of Cell Death and TherapyKU LeuvenBelgium
| | - Alexandra Papaioannou
- INSERM U1242University of RennesFrance
- Centre de Lutte Contre le Cancer Eugène MarquisRennesFrance
| | - Franziska Püschel
- Cell Death Regulation GroupOncobell ProgramBellvitge Biomedical Research Institute (IDIBELL)BarcelonaSpain
| | - Maria Livia Sassano
- Department Cellular and Molecular MedicineLaboratory of Cell Death and TherapyKU LeuvenBelgium
| | - Josip Skoko
- Institute of Cell Biology and ImmunologyUniversity of StuttgartGermany
| | - Patrizia Agostinis
- Department Cellular and Molecular MedicineLaboratory of Cell Death and TherapyKU LeuvenBelgium
| | - Jackie de Belleroche
- Neurogenetics GroupDivision of Brain SciencesFaculty of MedicineImperial College LondonUK
| | - Leif A. Eriksson
- Department of Chemistry and Molecular BiologyUniversity of GothenburgGöteborgSweden
| | - Simone Fulda
- Institute for Experimental Cancer Research in PaediatricsGoethe‐UniversityFrankfurtGermany
| | | | - Sandra Healy
- Apoptosis Research CentreNational University of IrelandGalwayIreland
| | - Andrey Kozlov
- Ludwig Boltzmann Institute for Experimental and Clinical TraumatologyAUVA Research CentreViennaAustria
| | - Cristina Muñoz‐Pinedo
- Cell Death Regulation GroupOncobell ProgramBellvitge Biomedical Research Institute (IDIBELL)BarcelonaSpain
| | - Markus Rehm
- Institute of Cell Biology and ImmunologyUniversity of StuttgartGermany
| | - Eric Chevet
- INSERM U1242University of RennesFrance
- Centre de Lutte Contre le Cancer Eugène MarquisRennesFrance
| | - Afshin Samali
- Apoptosis Research CentreNational University of IrelandGalwayIreland
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41
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Szalai P, Parys JB, Bultynck G, Christensen SB, Nissen P, Møller JV, Engedal N. Nonlinear relationship between ER Ca 2+ depletion versus induction of the unfolded protein response, autophagy inhibition, and cell death. Cell Calcium 2018; 76:48-61. [PMID: 30261424 DOI: 10.1016/j.ceca.2018.09.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 08/25/2018] [Accepted: 09/13/2018] [Indexed: 12/20/2022]
Abstract
Endoplasmic reticulum (ER) Ca2+ depletion activates the unfolded protein response (UPR), inhibits bulk autophagy and eventually induces cell death in mammalian cells. However, the extent and duration of ER Ca2+ depletion required is unknown. We instigated a detailed study in two different cell lines, using sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) inhibitors to gradually reduce ER Ca2+ levels in a controlled manner. Remarkably, UPR induction (as assessed by expression analyses of UPR-regulated proteins) and autophagy inhibition (as assessed by analyses of effects on starvation-induced bulk autophagy) required substantially higher drug concentrations than those needed to strongly decrease total ER Ca2+ levels. In fact, even when ER Ca2+ levels were so low that we could hardly detect any release of Ca2+ upon challenge with ER Ca2+ purging agents, UPR was not induced, and starvation-induced bulk autophagy was still fully supported. Moreover, although we observed reduced cell proliferation at this very low level of ER Ca2+, cells could tolerate prolonged periods (days) without succumbing to cell death. Addition of increasing concentrations of extracellular EGTA also gradually depleted the ER of Ca2+, and, as with the SERCA inhibitors, EGTA-induced activation of UPR and cell death required higher EGTA concentrations than those needed to strongly reduce ER Ca2+ levels. We conclude that ER Ca2+ depletion-induced effects on UPR, autophagy and cell death require either an extreme general depletion of ER Ca2+ levels, or Ca2+ depletion in areas of the ER that have a higher resistance to Ca2+ drainage than the bulk of the ER.
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Affiliation(s)
- Paula Szalai
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership for Molecular Medicine, University of Oslo, Norway; Danish Research Institute of Translational Neuroscience (DANDRITE), Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus, Denmark
| | - Jan B Parys
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine and Leuven Kanker Instituut (LKI), Leuven, Belgium
| | | | - Poul Nissen
- Centre for Membrane Pumps in Cells and Disease (Pumpkin), Danish Research Foundation, Aarhus, Denmark; Danish Research Institute of Translational Neuroscience (DANDRITE), Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus, Denmark
| | - Jesper V Møller
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Nikolai Engedal
- Centre for Molecular Medicine Norway (NCMM), Nordic EMBL Partnership for Molecular Medicine, University of Oslo, Norway.
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42
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Bergmann TJ, Molinari M. Three branches to rule them all? UPR signalling in response to chemically versus misfolded proteins-induced ER stress. Biol Cell 2018; 110:197-204. [PMID: 29979817 DOI: 10.1111/boc.201800029] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 06/15/2018] [Indexed: 12/16/2022]
Abstract
Study of the unfolded protein responses (UPR) is mainly addressed by challenging eukaryotic cells with chemical compounds that impair calcium, redox or glycan homeostasis. These dramatically alter the endoplasmic reticulum (ER) environment and function, but also trigger pleiotropic effects that may result in multi-organellar failure and cell death. Recent works showed that UPR induced by the accumulation of unfolded polypeptides in the ER lumen drastically differs from chemically induced UPR. Unfolded proteins are tolerated by cells, which activate a finely tuned UPR without entering apoptotic programs. How cells adapt the UPR to the burden of misfolded proteins, what structural features of the accumulating proteins determine UPR intensity and how these mechanisms translate into disease are crucial questions to be address in the future.
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Affiliation(s)
- Timothy J Bergmann
- Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, Institute for Research in Biomedicine, Bellinzona, Switzerland
| | - Maurizio Molinari
- Università della Svizzera italiana (USI), Faculty of Biomedical Sciences, Institute for Research in Biomedicine, Bellinzona, Switzerland.,École Polytechnique Fédérale de Lausanne, School of Life Sciences, Lausanne, Switzerland
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43
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Wang Q, Yuan X, Chen Y, Zheng Q, Xu L, Wu Y. Endoplasmic Reticulum Stress Mediated MDRV p10.8 Protein-Induced Cell Cycle Arrest and Apoptosis Through the PERK/eIF2α Pathway. Front Microbiol 2018; 9:1327. [PMID: 29977231 PMCID: PMC6021497 DOI: 10.3389/fmicb.2018.01327] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 05/30/2018] [Indexed: 12/14/2022] Open
Abstract
In this study, the mechanism of Muscovy duck reovirus (MDRV) p10.8 protein-induced pathogenesis was investigated, with a focus on endoplasmic reticulum (ER) stress. In chicken embryo fibroblasts cell lines (DF1), pCI-neo-flg-p10.8 protein transfection increased the phosphorylation (p-) levels of PERK and eIF2α as shown by Western blotting analysis and led to the dissociation of BiP from PERK as shown by co-immunoprecipitation (Co-IP) analysis. Results of treatment with both ER stress activator and inhibitor further confirmed that p10.8 protein induced ER stress. Subsequently, using flow cytometry analysis, it was also found that p10.8 protein induced cell cycle arrest during the G0/G1 phase. Furthermore, p10.8 transfection increased the phosphorylation levels of PERK and eIF2α, and reduced the expression levels of CDK2, CDK4, and Cyclin E according to Western blotting analysis. Treatment with ER stress activator and ER stress inhibitor after p10.8 protein transfection in DF1 cells further indicated that p10.8 protein induced ER stress, which resulted in cell cycle arrest. The results of knockdown of either PERK or eIF2α genes further confirmed that p10.8 protein-induced ER stress led to cell cycle arrest through the PERK/eIF2α pathway. Further results showed that p10.8 protein induced ER stress and apoptosis in DF1 cells. The expression levels of p-PERK, p-eIF2α, CHOP, cleaved-Caspase12, and cleaved-Caspase3 were increased by p10.8 protein. Test results of treatment with each of Tunicamycin, TUDCA and knockdown of PERK, and eIF2α, confirmed that p10.8 protein induced ER stress involving apoptosis via the PERK/eIF2α pathway. In conclusion, MDRV p10.8 protein induced ER stress that caused cell cycle arrest and apoptosis through the PERK/eIF2α pathway.
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Affiliation(s)
- Quanxi Wang
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Key Laboratory of Traditional Chinese Veterinary Medicine and Animal Health, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiaoqin Yuan
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Key Laboratory of Traditional Chinese Veterinary Medicine and Animal Health, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yuan Chen
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Key Laboratory of Traditional Chinese Veterinary Medicine and Animal Health, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Qingli Zheng
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou, China.,Fujian Key Laboratory of Traditional Chinese Veterinary Medicine and Animal Health, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Lihui Xu
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yijian Wu
- College of Animal Science, Fujian Agriculture and Forestry University, Fuzhou, China
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44
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Abdullah A, Ravanan P. The unknown face of IRE1α - Beyond ER stress. Eur J Cell Biol 2018; 97:359-368. [PMID: 29747876 DOI: 10.1016/j.ejcb.2018.05.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 05/03/2018] [Accepted: 05/03/2018] [Indexed: 12/16/2022] Open
Abstract
IRE1α (Inositol Requiring kinase Enzyme 1 alpha), a transmembrane protein localized to the endoplasmic reticulum (ER) is a master regulator of the unfolded protein response (UPR) pathway. The fate determining steps during ER stress-induced apoptosis are greatly attributed to IRE1α's endoribonuclease and kinase activities. Apart from its role as a chief executioner in ER stress, recent studies have shown that upon activation in the presence or absence of ER stress, IRE1α executes multiple cellular processes such as differentiation, immune response, progression and repression of the cell cycle. Besides its crucial role in protein misfolding, the versatile contributions of IRE1α in other cellular functions are greatly unknown. In this review, we have discussed the structural conservation of IRE1 among eukaryotes, the mechanisms underlying its activation and the recent understandings of the non-apoptotic functions of IRE1 other than ER stress-induced cell death.
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Affiliation(s)
- Ahmad Abdullah
- Apoptosis and Cell Survival Research Lab, Department of Biosciences, School of Biosciences and Technology, VIT University, Vellore, Tamil Nadu, India
| | - Palaniyandi Ravanan
- Apoptosis and Cell Survival Research Lab, Department of Biosciences, School of Biosciences and Technology, VIT University, Vellore, Tamil Nadu, India.
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45
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Bergmann TJ, Fregno I, Fumagalli F, Rinaldi A, Bertoni F, Boersema PJ, Picotti P, Molinari M. Chemical stresses fail to mimic the unfolded protein response resulting from luminal load with unfolded polypeptides. J Biol Chem 2018; 293:5600-5612. [PMID: 29453283 DOI: 10.1074/jbc.ra117.001484] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/23/2018] [Indexed: 12/16/2022] Open
Abstract
The stress sensors ATF6, IRE1, and PERK monitor deviations from homeostatic conditions in the endoplasmic reticulum (ER), a protein biogenesis compartment of eukaryotic cells. Their activation elicits unfolded protein responses (UPR) to re-establish proteostasis. UPR have been extensively investigated in cells exposed to chemicals that activate ER stress sensors by perturbing calcium, N-glycans, or redox homeostasis. Cell responses to variations in luminal load with unfolded proteins are, in contrast, poorly characterized. Here, we compared gene and protein expression profiles in HEK293 cells challenged with ER stress-inducing drugs or expressing model polypeptides. Drug titration to limit up-regulation of the endogenous ER stress reporters heat shock protein family A (Hsp70) member 5 (BiP/HSPA5) and homocysteine-inducible ER protein with ubiquitin-like domain 1 (HERP/HERPUD1) to levels comparable with luminal accumulation of unfolded proteins substantially reduced the amplitude of both transcriptional and translational responses. However, these drug-induced changes remained pleiotropic and failed to recapitulate responses to ER load with unfolded proteins. These required unfolded protein association with BiP and induced a much smaller subset of genes participating in a chaperone complex that binds unfolded peptide chains. In conclusion, UPR resulting from ER load with unfolded proteins proceed via a well-defined and fine-tuned pathway, whereas even mild chemical stresses caused by compounds often used to stimulate UPR induce cellular responses largely unrelated to the UPR or ER-mediated protein secretion.
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Affiliation(s)
- Timothy J Bergmann
- From the Università della Svizzera italiana, 6900 Lugano, Switzerland.,the Institute for Research in Biomedicine, 6500 Bellinzona, Switzerland.,the Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Ilaria Fregno
- From the Università della Svizzera italiana, 6900 Lugano, Switzerland.,the Institute for Research in Biomedicine, 6500 Bellinzona, Switzerland.,the Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Fiorenza Fumagalli
- From the Università della Svizzera italiana, 6900 Lugano, Switzerland.,the Institute for Research in Biomedicine, 6500 Bellinzona, Switzerland.,the Graduate School for Cellular and Biomedical Sciences, University of Bern, 3001 Bern, Switzerland
| | - Andrea Rinaldi
- From the Università della Svizzera italiana, 6900 Lugano, Switzerland.,the Istituto Oncologico di Ricerca, 6500 Bellinzona, Switzerland, and
| | - Francesco Bertoni
- From the Università della Svizzera italiana, 6900 Lugano, Switzerland.,the Istituto Oncologico di Ricerca, 6500 Bellinzona, Switzerland, and
| | - Paul J Boersema
- the Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Paola Picotti
- the Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Maurizio Molinari
- From the Università della Svizzera italiana, 6900 Lugano, Switzerland, .,the Institute for Research in Biomedicine, 6500 Bellinzona, Switzerland.,the École Polytechnique Fédérale de Lausanne, School of Life Sciences, 1015 Lausanne, Switzerland
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46
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Sauzay C, Voutetakis K, Chatziioannou A, Chevet E, Avril T. On the notion of doll's eyes. Front Cell Dev Biol 1984; 7:66. [PMID: 31080802 PMCID: PMC6497726 DOI: 10.3389/fcell.2019.00066] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/09/2019] [Indexed: 12/12/2022] Open
Abstract
CD90 is a membrane GPI-anchored protein with one Ig V-type superfamily domain that was initially described in mouse T cells. Besides the specific expression pattern and functions of CD90 that were described in normal tissues, i.e., neurons, fibroblasts and T cells, increasing evidences are currently highlighting the possible involvement of CD90 in cancer. This review first provides a brief overview on CD90 gene, mRNA and protein features and then describes the established links between CD90 and cancer. Finally, we report newly uncovered functional connections between CD90 and endoplasmic reticulum (ER) stress signaling and discuss their potential impact on cancer development.
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Affiliation(s)
- Chloé Sauzay
- INSERM U1242, Proteostasis and Cancer Team, Chemistry Oncogenesis Stress Signaling, Université de Rennes 1, Rennes, France
- Centre Eugène Marquis, Rennes, France
| | - Konstantinos Voutetakis
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, Athens, Greece
- Department of Biochemistry and Biotechnology, University of Thessaly, Larissa, Greece
| | - Aristotelis Chatziioannou
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, Athens, Greece
- e-NIOS Applications PC, Kallithea-Athens, Greece
| | - Eric Chevet
- INSERM U1242, Proteostasis and Cancer Team, Chemistry Oncogenesis Stress Signaling, Université de Rennes 1, Rennes, France
- Centre Eugène Marquis, Rennes, France
- Rennes Brain Cancer Team (REACT), Rennes, France
| | - Tony Avril
- INSERM U1242, Proteostasis and Cancer Team, Chemistry Oncogenesis Stress Signaling, Université de Rennes 1, Rennes, France
- Centre Eugène Marquis, Rennes, France
- Rennes Brain Cancer Team (REACT), Rennes, France
- *Correspondence: Tony Avril,
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